The World Flora Online

Herbs perennial, aquatic. Rhizomes branched, repent, forming swollen terminal storage tubers late in growing season. Leaves arising from rhizome, alternate, emersed or floating, long petiolate; leaf blade centrally peltate, veins radially extended. Flowers solitary, axillary, long pedunculate, bisexual, hypogynous, actinomorphic, entomophilous, borne above water surface. Tepals numerous, distinct, outermost reduced, inner ones larger and petaloid. Stamens numerous; anthers dehiscent by longitudinal slits. Pistils numerous, simple, separately and loosely embedded in cavities on flattened top of receptacle. Ovary 1-loculed; ovule 1, pendulous; styles very short; stigmas capitate. Fruit nutlike, indehiscent. Seeds without endosperm and perisperm; embryo large; cotyledons 2, fleshy.

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Herbs , perennial, aquatic, rhizomatous; roots adventitious; air chambers conspicuous in vegetative portions of plant. Rhizomes branched, repent, slender, terminal portions becoming tuberous-thickened late in growing season. Leaves arising directly from rhizome, alternate, floating or emersed; petiole long. Leaf blade peltate, orbiculate, margins entire; laticifers present. Inflorescences axillary, solitary flowers. Flowers bisexual, protogynous, diurnal, borne above water surface; peduncle long; involucre absent; perianth not persistent in fruit (outermost tepals of N . lutea normally persistent), hypogynous; tepals numerous, distinct, outermost reduced, inner tepals becoming larger and more petaloid; stamens numerous; filaments slender; anthers dehiscing by longitudinal slits, connective appendage incurved; pistils numerous, 1-carpellate, separately embedded in flattened top of turbinate receptacle; ovary 1-locular; placentation apical; ovule 1; style short; stigma nearly sessile, capitate. Fruits nutlike, indehiscent, loose in cavities of strongly accrescent receptacle. Seed 1, aril absent; endosperm and perisperm absent; embryo completely filling seed; cotyledons 2, fleshy.

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Fls perfect, regular, hypogynous; tep numerous, spirally arranged, a few outer ones green and sepaloid, the others petaloid; stamens numerous (ca 200) spirally arranged; pollen tricolpate; pistils numerous (ca 10–40); individually sunken in (but free from) the enlarged, obconic, spongy receptacle, only the sessile stigma protruding; ovule solitary, pendulous; fr of separate, hard- walled nuts loose in the cavities of the accrescent receptacle; seed solitary, filled by the large, dicotyledonous embryo; pls aquatic; lvs arising directly from the rhizome, alternate, long-petiolate, with large, circular, centrally peltate blade, some blades floating, others raised above the water; fls elevated above the water on long, stout peduncles arising from the rhizome. 1/2.

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Herbes pérennes, aquatiques, rhizomateuses, lactifères; rhizome branchue, à parties terminales tubérisées et épaissies vers la fin de la saison de végétation. Stipules présentes, engainantes. Feuilles provenant directement du rhizome, alternes, distiques, peltées, sous-tendues par deux cataphylles charnus ; pétiole attaché au milieu du limbe ; limbe ± circulaire, à marge entière; nervation actinodrome. Inflorescences axillaires, à fleurs solitaires ; bractées présentes, sous-tendant la fleur. Fleurs acycliques (sans calice ni corolle distincts), bisexuées, actinomorphes, grandes ; périanthe à de nombreux (14 à 30) tépales libres, les internes plus grands et plus colorés que les externes ; étamines nombreuses, ± 100 à 400, spiralées, anthères à déhiscence par fentes longitudinales, connectif claviforme ; gynécée apocarpe, à de nombreuses pistils unicarpellés, intégrés dans le réceptacle turbiné et à sommet plat, ovaire hypogyne, 1-loculaire, à 1 ovule apical ; style unique, court, à stigmate capité. Fruits indéhiscents, en noyaux, chacun libre dans une cavité du réceptacle fortement accrescent. Graines exalbuminées, sans arillode ni périsperme.

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Famille avec un seul genre présent en Amérique du Nord jusqu’aux Antilles et en Asie, connu en culture ailleurs, y inclus au Gabon.

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• 10
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SELECTED REFERENCES

Wood, C. E. Jr. 1959. The genera of the Nymphaeaceae and Ceratophyllaceae in the southeastern United States. J. Arnold Arbor. 40: 94-112.

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